Medicament-dispensing cartridge



Dec. 3, 1929. P. G. A'l-rnzlNEMAN ETAL v 1,737,844

v MEDICAMENT DsPENsING CARTRIDGE Filed Jan. 26. 1927 one of which'is designed to be pierced by a ing canula thereon, and having Paie-med Der'. 3, 1929 "UNITED STATES PATENT OFFICE IAUL'G. IIEINEMAN AND HENRY E. o; HEINEMAN, OE CHICAGO, ILLINOIS, Assrenonsl To coox LABORATORIES, mc., A CORPORATION OE DELAWARE MEnIcAMENT-DIsrENsIN'e CARTRIDGE Application ld January 26, 1927. Serial No, 163,639.

This invention relates tov improvements in medicament dispensing cartridges of the type wherein a tube oi'glass is sealed at opposite ends by rubber composition plugs,

canula to establish communication with the interior of the cart-ridge, the ot-her plug being slidable through the cartridge body to expel the medicament through the canula. Among other objects, the invention aims to minimize stickingpf the slidable plug Within the tubular cartridge. v f

The invention may be understood by reference to fone' illustrative embodiment shown in the accompanying drawings, in which Fig. 1 is a longitudinal section of a medicament dispensing cartridge shown in a commercial form of syringe; and Fig. 2 is a perspective view of the slidable rubber plug for the cartridge.

Medicament dispensing cartridges of the described type are now established Aarticles of commerce. They are used primarily to provide charges of medicament when associatedl with a syringe or syringe-like structure having means for securing a cartridge-pierca plunger movable to force the slidable plug through the cartridge to dispense the medicament. In the injection of certain medicaments, for instance local anesthetics, it is sometimes desirable to inject a portion ont the contentsv of the cartridge at one point in the tissue andE then Withdraw the syringe and make another injection in a different location. For example, in a mandibular injection for the `ex traction of the molars and bicuspids, from l@ cc. to 1/2 cc. of anesthetic is injected. into the lingual nerve, 1% cc. to 2 cc. inthe inferior dental nerve, and lf2 cc. in the long buccal nerve, this making 21/4 cc. to 3 cc. in all. When using a cartridge syringe in suchv an injection, considerable pressure is exerted onlthe plun er to force the medicament through the e bore of the needle into the `tissue. VWhen pressure is exerted on the plunger, the mid portion of an ordinary slidable rubber plug is pushed by the plunger ahead of the peripheral portion of the plug due to the tendency of the compressed plug to adhere to the walls of the tubular cartrid e body.' .Now when pressure is released, t e

inid portion of the plunger plug being no longer under pressure, automatica y returns to its initial position, and this movement of. the mid portionlof the plug creates a certain suction which is sometimes eiective to draw up a minute quantity of blood into the partially emptied cartridge. This is objectionable in view of using a single cartridge during a series of injections on a patient, and particularly if injections from a single cartridge should be made in more than one patient.

The present invention aims to provide a medicament cartridge whose plunger plug, though adequately long and tight for sealing purposes, is -not liable to stick or so adhere to the glass cartridge tube as to induce such distortion by'plunger thruts as would result in sucking-back action `when theapplied pressure is released.

Referring specifically to the drawings, there is shown a syringe-like structure for use with a medica-ment dispensing cartridge embodying the invention.' The syringe-like structure comprises a body 5 having a hinged head 6, a slidable plunger 7 carried by the head and movable through it an'd entering the body to eject the medicament. At the opposite end of the body a canula or needle 8 is secured, said canula being shown as pointed at both ends and arranged so as to penetrate one wall of the cart-ridge to establish communication with the interior of the cartridge without admitting air or permitting loss of the medicament. The cartridge shown and syringe embodyin it are of substantially the construction disc osed and claimed in the MacGregor applications Serial Nos. 713,902 and 713,903, iled May 17, 1924, and the cartridge consists of as straight tube 9 of lass sealed at the fore end by a pierceable ru ber composition plug 10 and sealed at the opposite end by a slidable rubber composition 'l plug 11, the medicament` being coniined between the two plugs when the cartridge is full. Preferably, the pierceable plug'lO is provided with an integral flange 12 Overlapping the end of the glass tube'9 and having a recess 1,3 to facilitate piercing and to en= l hance the sealing qualities of the plug, parsimilar wax, when a rubber plug of such composition is inserted under pressure in the end ofacartridge,the paraffin seems to be squeezed out of the invisible -pores of the plug, and. seems to forman invisible film or. coating on the outside surface of the rubber plug, which causes it to slide very freely and easily through a glass tube, so that there is no sucking-back action upon relief of pressure. We prefer to employ about 1.5% by weight of purified paraffin, although variations from this percentage are permissible.v However, one must not incorporate a large percentage of paraffin inthe rubber, otherwise the physical characteristics of the plug are so greatly modified that it does not satisfactorily seal the cartridge; nor is a much lower percentage of paraffin effectual to eliminate the described sucking-back tendency. l l

Further to insure free sliding through the glass tube, we prefer to coat each rubber plug, made as described, with a film of pure glycerin, a substance which has been selected because it does not react with most medicaments, nor with the glass and rubber bodies which comprise the cartridge. However, it is possible to use other lubricants and we do not Wish to be limited to the use of glycerin for this purpose. The glycerin does not evaporate from between the plug and the lass tube, but remains as a permanent coating on the periphery of the slidable rubber plug, and even after a lapse of considerable time', when all rubber lugs show a tendency to become hard and brittle (probably due to oxidation of the rubber), the glycerin will prevent sticking of the rubber' plug to the glass walls of the tube and will therefore greatly facilitate use of the cartridge in an injection. We have found that the use of- -glcerin is. not necessary when the slidable ru ber plug is im regnated with 'parafiin and then inserted un er pressure into the end of the glass tube; nevertheless the addition of a v coating of glycerin is preferred because it makes the action of the slidable plug somewhat easier. The glycerin also greatly facilitates insertion of the plugs in the ends' of the glass tubes, without very frequent breaking of the tubes. Glycerin alone will not pre- A vent the sucking-back tendency.

The glycerin may be applied by immersing the plugs in a vessel containing glycerin forl twenty-four to forty-eight hours, during 'upon the plugs during insertion in the glass tube. These chambers, when filled or partially filled with glycerin, apparently enhance the sealin action of the plug. As the plug is pushed t rough-the glass tube an invisible film of glycerin proba ly spreads over the surface of the glass in advance of the plug, thus making the plug easily slidable,

even when it is very tightly compressed within the tube, and has been in position for many months.

Thepierceable plu 10, shouldnotbe im- I pregnated with para n or any4 other `substance calculated to facilitate movement relative to the glass tube,.nor should it be coated with glycerin or yany1 other lubricant. It should be immovable during ejection of the medicament, otherwise part or all of the'.

medicament may escape past it and be lost.

Obviously the present invention is not restricted to the particular `embodiment thereof herein shown and described. Moreover, it is not indispensablethat all the features of the invention be used conjointly since they may be employed advanta eously in Various combinations and subcombinations as defined in the claims.

What we claim is: v

1 A medicament dispensing cartridge comprising, in combination, a straight tube of glass; a readily pierceable rubber composition plug inserted in and sealing one end of said tube and having an axial recess lfacing inwardly of the cartridge and also having an integral flange lap the end of t e glass tube; said plug being free from lubricants, whether coated thereon or impregnated therein; and `another rubber composition plug initially sealing the opposite end of the cartridge and slidable through the tube; said slidable plug impregnated with paraffin in sufficient quantity to minimize sticking 'of the plug to the inside of the glasstube or'su'ch adherence of the plug to the glass tube as will cause a suckplrojecting radially to overing-back action when pressure, put on. the

plug to dispense the medicament, is relieved.

2. A medicament dispensing cartridge comprising, in combination, a straight tube of glass; a readily pierceable rubber composition plug inserted` in and sealing one end of said tube; said plug being free from lubricants, whether coated thereon or impregnated therein; and another rubber composition plug initially sealing the opposite end of the cartridge and slidable through the tube; said slidable plug impregnated with araliin inl sufficient quantity to minimize stic ing of the plug to the inside of the glass tube or such adherence of the plug to the glass tube as will cause a sucking-back"action when pressure, put on the plug to dispense the medicament, is relieved!` Y 3. A medicament dispensing cartridge comprising, in combination, a straight tube; a readily pierceable closure sealin one end of said tube; and a rubber composition plug initially sealing the opposite endeof the cartridge and slidable through' the tube; said slidable plug impregnated with paraiiin in suicient quantity to minimize sticking of the plug to the inside of the tube or such adherence of the plug to the tube as will cause a` sucking-back action when pressure, put on the'plug to dis ense the medicament, is ref lieved; said sli able plug also coated with a neutral liquid lubricantsuch as will materially facilitate sliding through the tube. v

'4. A medicament dispensing cartridge comprising, in combination, a straight tube;

I a readily pierceable closure inserted in and sealing one end of saidtube; and a rubber composition plug initially sealin the 'opposite end of the cartrid e an slidable through the tube; said slida le plug impregnated with paraiiin in sufficient quantity to minimize stlcking of the plug to the inside of the tube orsuch adherence of the plug to the tube as will cause a sucking-back when pressure, put on the plug to dispense the'medicament, is relieved ;said slidable plug having a circumferential groove and having a action comprising a rubber composition plug impregnated with araiiin in suiiicient quantit to minimize stic ing of the plug or such a herence thereof to the tube as would causesucking-back action when the pressure ap-v 9. A syringe cartridge comprising aglassV tube having liquid-confining Stoppers, one

adapted to be` pierced by and to seal around a needle, the other adapted to be pushed inward to eject the liquid through the needle; said inwardly-pushable stopperbeing' 0f a rubber composition inpregnated with a small amount of parain in appropriate amount for the purpose" described, and having also a lubricating ilm of glycerin.

v In testimony whereof, we have signed our names to this s ecification.

PA L G. HEINEMAN. .HENRY E. O. HEINEMAN.

{ilm of glycerin theron to facilitate its slid-I e ing.

5. As an article of manufacture, a syringe cartridge stopper of composition rubber im-' pregnated with about 1.5% by weight of paraffin, said stopperl adapted .to be inserted v under compression in a cartridge tube and to be slidable therein.

6. Asyringe cartridge comprising a glass tube havin liquid-connin Stoppers,` one adapted to 'be plerced by an to .seal around a `needle, the other slidable in the tube and adapted to be pushed inward by a plunger to .eject the 1i uid through the needle; sald inv wardly-pus able stopper being of a rubber composition impregnated with a neutral waxy substance in insuiiicient amount to impair desired resiliency and sealing capability of the stopper but suilicient to' prevent such adherence of the stopperl to the glass as would cause sucking-back action when the applied pressure is relieved. n

7. A syringe cartridge comprising a glass tube having sealing Stoppers one offwhich is slidable in the tube and adapted to be pushed inward by a plunger for ejecting the containediluid through a needle thrust through 'the opposite stopper, said slidable stopperl l 

